下面的C++代码实现对 lst 的快速排序，有关说法，错误的是（ ）。

vector<int> operator +(vector<int>lA, vector<int>lB)
{
    vector<int>lst;

    for (int i = 1; i < lA.size(); i++)
        lst.push_back(lA[i]);
    for (int i = 1; i < lB.size(); i++)
        lst.push_back(lB[i]);

    return lst;
}

vector<int>qSort(vector<int>lst)
{
    if (lst.size() < 2)
        return lst;
    int pivot = lst[0];
    vector<int>less, greater;
    for (int i = 1; i < lst.size(); i++)
        if (lst[i] <= pivot) less.push_back(lst[i]);
        else greater.push_back(lst[i]);
    for (int i = 1; i < lst.size(); i++)
        if (lst[i] <= pivot) less.push_back(lst[i]);
        else greater.push_back(lst[i]);

    return ________________________________________;
}

{{ select(1) }}

• qSort(less) + qSort(greater) + (vector<int>)pivot
• (vector<int>)pivot + (qSort(less) + qSort(greater))
• (qSort(less) + (vector<int>)pivot + qSort(greater))
• qSort(less) + pivot + qSort(greater)